1. Field
Aspects of embodiments according to the present invention are directed toward a method of stacking disk-shaped substrates and an apparatus for implementing the method.
2. Description of Related Art
Numerous situations to assemble disk-shaped substrates, such as a disk platter for a magnetic hard drive, as a stack appear in glass substrate manufacturing processes. For example, a magnetic hard drive stores data on a disk platter including one or more concentrically arranged disk-shaped substrates. Each of the disk-shaped substrates has a hole at the center and may be a glass substrate. In general, a disk-shaped substrate has predetermined outside diameter (OD) and inside diameter (ID) (i.e., diameter of the hole). During manufacturing of the glass substrate, the inside circumferential surface of the hole is polished to the desired smoothness. Similarly, the outside circumferential surface of the substrate is polished.
In the related art, a number of disk-shaped substrates are stacked in a concentric manner to form a stack or column such that the inner circumferential surfaces of the disk-shaped substrates can be polished together to save time and costs. A typical method to assemble a stack of disk-shaped substrates uses a centering shaft or a guide shaft that has a tight tolerance relative to the ID of the disk-shaped substrate. Although the centering shaft can maintain the concentricity of the disk-shaped substrates, the use of the centering shaft may cause damage to the inside circumferential surfaces (e.g., edges) of the disk-shaped glass substrates. Therefore, it is desirable to provide an improved method of stacking and aligning disk-shaped substrates while avoiding damage to the inside circumferential surfaces of the substrates, and it is also desirable to provide an apparatus to practice the improved method.